The need to connect a new drain to a drain pipe often arises during building renovations or refurbishment projects. In such instances, the new drain usually includes an insert pipe that has an outer diameter that is smaller than the outer diameter of the drain pipe. A variety of couplings have been developed to join the insert pipe to the drain pipe. For example, it is very common for installers to use a rubber flexible sleeve coupling that fits around and over the top of the standing drain pipe and the bottom of the insert pipe, and is tightly secured in place to each by circular steel band clamps are tightened with screws. While the design of this coupling sleeve is relatively simple and installation of the coupling can be performed relatively easily, the use of this type of coupling may not be well-suited in certain applications where access to the standing drain pipe may be limited or difficult, or where space constraints hinder the installer's ability to properly tighten the steel band clamps.
To address these drawbacks, certain couplings have been configured to fit into the insert pipe and the standing drain pipe. One such coupling is described in Canadian Patent No. 2,698,587 issued to Abbasi et al. The coupling includes an articulated housing which is made up of two solid tubular bodies that are threaded to each other. The tubular bodies are outfitted with an elastic tubular cover which surrounds them. The elastic tubular cover extends along almost the entire length of the tubular bodies and is held in place by two end collars—one collar associated with one of tubular bodies disposed at one end of the articulated housing and the other collar associated with the other tubular bodies located at the opposite end of the articulated housing. One of the collars is provided with a castlehead which is configured to receive a special, bar-shaped tool which allows torque to be applied to the associated tubular body.
During installation, the articulated housing is inserted into the insert pipe and then both the articulated housing and the insert pipe are inserted into the standing drain pipe. Thereafter the special tool is mated with the castlehead provided on the collar and the associated tubular body is urged to rotate and move towards the other tubular body. As this occurs, the span between the two end collars shortens thereby squeezing or compressing the elastic tubular cover between the collars. This compression deforms the elastic tubular cover and causes it to expand outwardly to sealably contact the inner surfaces of the insert pipe and the standing drain pipe.
While this coupling constitutes an improvement over the rubber flexible sleeve described above, in the field some difficulties have been encountered. More specifically, due to its design, the elastic tubular body must be deformed in order to form a seal with the inner surfaces of both the insert pipe and the standing drain pipe. Sometimes, during installation, if the elastic tubular cover does not sufficiently deform, it can fall through the standing drain pipe and can get lodged therein. Retrieval of the lodged coupling can be a difficult and costly undertaking.
A similar problem can be encountered when an installer wishes to disconnect an already installed coupling. It is not possible to separately disconnect the coupling from the insert pipe or the standing drain pipe. In order to disconnect an already installed coupling, the installer has to lengthen the tubular bodies to cause the elastic tubular cover to revert to its non-expanded configuration. When the installer does so, the coupling is simultaneously loosened from both the insert pipe and the standing drain pipe.
Moreover, because of the rigidity and limited sizing options of the tubular bodies, the coupling cannot accommodate a broad range of pipe sizes.
In light of the foregoing, it would be desirable to have a coupling assembly that could be tighten or “locked” in place to each of the standing pipe drain and the insert pipe, independently. Preferably, such coupling assembly would be configured to minimize the risk of it falling into, and becoming lodged in, the standing drain pipe.